The present invention generally relates to pharmaceutical compositions and methods of making the same.
Amino acid-based materials, particularly high molecular weight amino acid-based materials such as peptides, proteins, and enzymes, are known to be useful in a number of therapeutic indications. For example, materials such as somatostatin and somatotropin are typically employed as growth hormone regulators. Additionally, somatostatin may be used in the treatment of hemorrhage of gastro-duodenal ulcers.
Traditionally, formulations containing these materials have been formed by various freeze-drying techniques. A solution containing an amino acid-based material is typically loaded into containers (e.g., vials) and the temperatures of the solutions are lowered until it is frozen. These temperatures may reach as low as -60.degree. C. The temperature of the solutions are then slowly raised, typically over the course of a number of days until the diluent is sublimed out under high vacuum, and the desired composition is obtained. The final composition is typically present in the form of a dried powder.
Notwithstanding any potential advantages, the above process suffers from various drawbacks. The freeze drying process is typically time consuming, tedious, and expensive in that it involves multiple steps over a prolonged period of time. Additionally, the processing equipment can limit the production batch size to what can fit into the lyophilizer. Moreover, the final product in the form of a dried powder comprising the peptides, enzymes, or proteins often must be maintained in a reduced temperature environment in order for the pharmaceutical materials to remain stable.
A method for forming immobilized enzymes by using a spray drying process is proposed in U.S. Pat. No. 5,051,362 to Soehiro. A given enzyme is disclosed to be dissolved in an aqueous solution of styrylpyridinium group- or styrylquinolinium group-containing poly(vinyl alcohol). The enzyme-containing aqueous solution is then spray dried, and the resulting dry particles are subsequently subjected to a photo-crosslinking step. The '362 patent may be considered disadvantageous because it requires using a specifically-tailored solvent material, namely the modified poly(vinyl alcohol). Moreover, the use of photo-crosslinking involves an additional operation which adds time and expense to the above process.
Thus, there is a need in the art for a process for producing amino acid-based materials which is more efficient than current conventional processes. For example, it would be advantageous if the process did not require a photo-crosslinking step. It would be desirable if such a process could utilize existing solvents, buffers, and the like. It would also be desirable to be able to produce large quantities of drug/drug product in one batch or a continuous process operation. Additionally, the ability to stabilize the amino acid-based materials in dry form without the need for refrigeration would be desirable.